Observations on tanning of the potato cyst-nematode,Globodera rostochiensis

Abstract

SUMMARYColour changes that occur during tanning of intact and puncturedGlobodera rostochiensisfemales and of isolated cuticle are described. Experiments with catechol and enzyme inhibitors show that the tanning enzyme, a phenoloxidase, is located in the cuticle, soluble in aqueous media and relatively abundant. Substrate for the enzyme is limited in the cuticle. Pseudocoelomic fluid of yellow females promoted tanning and contains either phenolic substrate(s) for the enzyme or part of a biochemical system responsible for release of the substrate. The substrate or biochemical system is thermolabile. Apparently, the tanning enzyme and its substrate(s) are partitioned in living females but the partitioning breaks down after death and the cuticle tans to form the cyst.